CC BY
32
Protistology ■ 15
We hypothesized that the population structure of planktonic grazers in a high productivity site differs from that known for typical oligotrophic sites. We expected the high productivity site to harbor more species. We compared a high productivity site with dense populations of N-fixing Trichodesmuim, and a distant oligotrophic site. We examined patterns of species abundance distribution and the abundance distribution of ecological types, that is species of similar shell or lorica oral diameter, analogous to gape size. We also examined species packing within ecological types, defined as lorica oral diameter size-classes. Population abundance differed between the sites by a factor of 3, and the productive site population was highly dominated by a single species (not found at the oligotrophic site) but species richness and turnover were very similar. Species abundance distributions for both sites on all dates most closely fit a log-series or lognormal distribution. Abundance distributions of ecological types, forms of distinct lorica oral diameter, were the typical geometric for the oligotrophic site. In contrast, at the high productivity site, lognormal or log-series distributions provided equally good fits. In the oligotrophic site there was a positive relationship between the number of individuals in a lorica size-class and the number of species but not in the productive site. Despite large differences in population size and dominance, the two populations were surprisingly similar by most measures. Our results suggest that overall food web structure is likely similar as well.
ARE SPECIALIZED TROGLOBIONT CILIA-TES EXIST? Dovgal I.V.
Kovalevsky Institute of Marine Biological Research [email protected]
The organisms inhabiting in subterranean waters can be separated into two groups. One of them is represented by species, which for any reasons being situated in the underground habitats and have adapted to them. As a rule, these are the same species as in epigean waters or soils and possible has originated from mentioned habitats. Thus, the group might denoted as epigean. Another group of organisms is represented by specialized troglobiont species. The list of ciliated protozoans living in subterranean waters comprises about 150 species, but most of them can be defined as representatives of epigean group. Only a few ciliate species, which are host-specific commensals or parasites of subterranean animals (especially crustaceans) possibly, should be considered as troglobionts. In
such a way, the list of specialized troglobiont ciliates must include suctorians Spelaeophrya troglocaridis from shrimps, Tokophrya bathynellae from syncarids, Echinophrya stenaselli and T. microcerberi from subterranean isopods. The analysis of literary and own data on distribution and host prevalence of suctorian ciliate T. niphargi from amphipods and peritrich ciliate Ballodora marceli from wood louses permit to define these ciliates to epigean group of species. As for apostomes Gymnodinioides sp. from cavernicolous amphipods and shrimps, status of these ciliates remains to be seen.
SPECIES DIVERSITY AND BIOTOPICAL DISTRIBUTION OF HETEROTROPHIC FLAGELLATES IN SMALL RIVER FLOODPLAIN Dubrovsky Yu.V.1, Mylnikov A.P.2
1 - Institute for Evolutionary Ecology of the Nacional Academy of Sciences of Ukraine (IEENAS of Ukraine), Laboratory ofWildlife Protection and Restoration
2 - Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Russia [email protected]
Twenty-seven species and forms of heterotrophic flagellates have been found in the result of analysis of 8 water and 4 soil samples (downstream ofriver Ros', Ukraine, 49°37'N; 31o30'E) during summer 2014. Observed species belongs to Opisthokonta (2 species), SAR (17), Excavata (8) and incertae sedis group (2). The most flagellates were bacterivorous. Allantion tachyploon, Kathablepharis sp., Alphamonas edax, Colponema vietnamica, Diphyleia rotans, Rhynchobodo armata belonged to predators and Goniomonas truncata and Paraphysomonas spp. were omnivorous. The relationship between locality of the sample and species composition has not been revealed. This fact indicates the random character of species distribution. The most abundant (9-13 species) were overgrown river floodplain creeks and ponds, as well as wet soil deciduous forest. The silted ponds and creeks without flow, as well as coastal soils, are characterized by the average species richness (6-7 species). River watercourse, dried puddle, bedrock at a depth of12 m and the soil under field crops possess the lowest species richness (2-4 species). The vast majority of species is common for all investigated biotopes and occurs both in water and in the soil. Among the 11 species occurring in more than three samples, 7 species are inhabited both water and soil, and 4 species were found only in water samples. The average number of species for water and soil samples (7 and 6 correspondingly) was not significantly differed. The specificity of species composition within habitats is not observed. This study was supported by the Russian Foundation for
